Electronic device manufacturers strive to produce a rich interface for users. Conventional devices use visual and auditory cues to provide feedback to a user. In some interface devices, kinesthetic feedback (such as active and resistive force feedback) and/or tactile feedback (such as vibration, texture, and heat) is also provided to the user, more generally known collectively as “haptic feedback” or “haptic effects.” Haptic feedback can provide cues that enhance and simplify the user interface. For example, vibration effects, or vibrotactile haptic effects, may be useful in providing cues to users of electronic devices to alert the user to specific events, or provide realistic feedback to create greater sensory immersion within a simulated or virtual environment.
Haptic feedback has also been increasingly incorporated in portable and mobile electronic devices, such as cellular telephones, smartphones, portable gaming devices, vehicle based devices and interfaces, and a variety of other portable and mobile electronic devices. For example, some portable gaming applications are capable of vibrating in a manner similar to control devices (e.g., joysticks, etc.) used with larger-scale gaming systems that are configured to provide haptic feedback.
In order to generate vibration or other effects, many devices utilize some type of actuator or haptic output device. Known actuators used for this purpose include an electromagnetic actuator such as an solenoid actuator, an Eccentric Rotating Mass (“ERM”) actuator in which an eccentric mass is moved by a motor, a Linear Resonant Actuator vibration motor (“LRA”), or a piezoelectric actuator. Each of these target haptic actuators receives a haptic control signal that provides the parameters for the haptic effect. However, for a particular haptic effect, the haptic control signal may need to be varied based on the actuator that provides the haptic effect. Thus, for one haptic actuator, the control signal may be one type of signal representing, for example, an on or off condition, while for another haptic actuator, the control signal may be another type of signal representing, for example, a position value.